JP3220602B2 - Multi-component simultaneous continuous analysis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for simultaneous and continuous analysis of multiple components. The present invention relates to a method of simultaneously and continuously analyzing multiple components by combining an FTIR (Fourier transform infrared spectroscopy) analyzer for quantitatively analyzing a concentration and another analyzer other than the FTIR analyzer.

[0002]

2. Description of the Related Art As disclosed in, for example, JP-A-4-262239 and JP-A-5-296923, the above-mentioned FTIR analyzer uses an exhaust gas (hereinafter referred to as an exhaust gas) discharged from an automobile engine or the like. , Sample gas) can be simultaneously and continuously analyzed. However, this FTIR analyzer has components that cannot be measured, such as oxygen (O ₂ ) and total hydrocarbons (THC).

[0003] Therefore, for example, the air-fuel efficiency (A
/ A F), if you want to know also the concentration of multi-component which can be measured by FTIR spectrometer, conventionally, as shown in FIG. 4, the O ₂ and THC in the sample gas, O _2, such as a magnetic oxygen analyzer T, hydrogen flame ionization detector (FID), etc.
It is measured by another analyzer 41 such as an HC meter, and those analyzers 4
1 and the output of carbon monoxide (CO), carbon dioxide (CO ₂ ), etc., from the FTIR analyzer 42,
The data must be input to an external computer 43 different from the computer 42A provided in the IR analyzer 42, and the computer 43 has to calculate using the outputs. In FIG. 4, arrows indicated by solid lines indicate signals, and arrows indicated by dotted lines indicate sample gases S.

[0004]

However, in the above-described analysis method, the FTIR analyzer 42 has a relatively large cell volume, a slow response speed as compared with the other analyzers 41, Due to differences in dead time (time to output), response speed (response rounding), and data output interval in 41 and 42, when looking at transient phenomena, the calculation is very complicated and the obtained value is also large. It has the disadvantage of being prone to inaccuracy. There is also a disadvantage that it is difficult to obtain a calculated value in real time.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned circumstances, and has a multi-component simultaneous continuous method capable of simultaneously and accurately analyzing a multi-component including a component which cannot be measured by an FTIR analyzer in real time. It aims to provide an analytical method.

[0006]

Means for Solving the Problems To achieve the above object, a method for simultaneous and continuous analysis of multiple components according to the present invention comprises the steps of :
FTIR to computer for control and data processing of analyzer
Directly read the instructions from other analyzers other than the
And the instructions of the FTIR analyzer are temporarily stored in the temporary storage unit.
Store and compensate for differences in dead time and response speed
After that, both instructions with almost the same timing and response speed
Display and output. That is , a computer for controlling and data processing of the FTIR analyzer is provided with the FTIR analyzer.
Instructions from other analyzers other than the analyzer are directly read, and these instructions are simultaneously handled in the computer together with the instructions of the FTIR analyzer. Further, a dedicated storage area for temporarily storing data (instructions) read in the computer is secured. Similarly, a storage area is also reserved for an instruction from the FTIR analyzer, and a constant number of the latest data up to the present time is always stored for each.

[0007] In the above multi-component simultaneous continuous analysis method,
The analyzed sample gas discharged from the analyzer of the TIR analyzer may be supplied as a sample gas to the analyzer of an analyzer other than the FTIR analyzer.

[0008]

FIG. 3 (A) is a graph showing a component a using an FTIR analyzer.
FIG. 7B shows an example of the instruction A when analyzing the data.
Shows an example of the instruction B when the component b is analyzed using, for example, a THC meter. The dead time in each of the instructions A and B is assumed to be T _A , T _B (where T _A > T _B ). FIG. 4C shows an example of simultaneous output of the components a and b and the component c calculated from the instructions A and B according to the present invention.

According to the present invention, the components a, b
Even if the dead time of the FTIR analyzer is different, the latest data A of the FTIR analyzer and the data temporarily stored in the storage area
Of the analyzer indicated, by using the (T _A -T _B) only, before the instruction B ', it is possible to correct the difference. Further, even when there is a difference in response speed, the response speed can be approximated by using a moving average of the indicated values stored for a faster analyzer. For this reason, instructions A and B (B ') of completely different analyzers, respectively,
Further, a component c calculated based on the instructions A and B ′
And an instruction C of the same analyzer can be obtained as an output with a uniform dead time and response speed from one analyzer (FTIR analyzer). This facilitates subsequent handling of the measurement data (indicated value).

[0010] When the sample gas discharged from the analyzer of the FTIR analyzer is supplied to the analyzer of another analyzer other than the FTIR analyzer, the sample gas in the FTIR analyzer and the other analyzer may be originally supplied. And the difference in the sampling conditions, such as the presence or absence of gas component loss in the piping on the way, is less likely to occur, and the above effect is further enhanced.

[0011]

1 and 2 show an embodiment of the present invention. First, in FIG. 1, reference numeral 1 denotes an analysis section (hereinafter referred to as an FTIR analysis section) of an FTIR analyzer, and an upstream side thereof is provided. ,
A sample gas introduction path 2 for supplying the exhaust gas as it is or appropriately diluted as a sample gas S is connected. Reference numeral 3 denotes an analyzer of another analyzer provided via a gas flow path 4 on the downstream side of the FTIR analyzer 1, reference numeral 5 denotes an overflow channel, and reference numeral 6 denotes a gas discharged from the analyzer 3 of the other analyzer. The flow path is shown. The details of these configurations will be described later with reference to FIG.

Reference numeral 7 denotes a computer (hereinafter simply referred to as a computer) for controlling and processing data of the FTIR analyzer.
An FTIR data processing unit 8 that controls the FTIR analysis unit 1 and processes data from the analysis unit 1 and an analysis unit 3 of another analyzer, and reads data from the analysis unit 3. A data reading unit 9 of the analyzer, a temporary storage unit 10 of an FTIR analyzer instruction for temporarily storing data processed by the FTIR data processing unit 8, and data read by the data reading unit 9 of another analyzer. A temporary storage unit 11 for temporarily storing instructions of other analyzers,
IR data processing unit 10 and data reading unit of other analyzers
9 and an arithmetic operation unit 12 for performing arithmetic processing on data from the temporary storage units 10 and 11. An operation / output unit 13 includes an input keyboard, a display unit, or a printer.

Next, FIG. 2 specifically shows an example of a gas sampling flow for carrying out the method of the present invention. In this figure, reference numeral 14 denotes a sample gas inlet;
A filter 15, a solenoid valve 16, a needle valve 17, a suction pump 18, a flow meter 19, and a filter 20 are provided in this order between the inlet 14 and the FTIR analyzer 1. An FTIR span gas line 21 includes an electromagnetic valve 22, a regulator 23, a needle valve 24, and the like. The upstream side is connected to a span gas source (not shown), and the downstream side is a pump of the sample gas introduction path 2. 18
And the flow meter 19.

A gas flow path 4 connecting the FTIR analysis section 1 and the analysis section 2 of another analyzer is provided with a solenoid valve 25, a suction pump 26, and a filter 27 in order from the upstream side.
And so on. An analysis section 3 of another analyzer is provided downstream of the gas flow path 4. In this embodiment, the other analyzers include, for example, a THC meter made of FID and a magnetic oxygen analyzer. an O ₂ meter consisting meter, their analysis unit 3A, 3B are connected in parallel to each other. 28 and 29 is a capillary for each flow rate adjustment is provided on the upstream side of the THC meter analyzer 3A, O ₂ meter analyzer 3B. And 30 is an analysis unit 3A, 3B
A regulator 31 and a flow meter 32 are connected in parallel with the overflow channel. Reference numeral 33 denotes a span gas line of another analyzer such as a THC meter, which includes a solenoid valve 34, a regulator 35, a needle valve 36, and the like. The upstream side is connected to a span gas source (not shown), and the downstream side is The gas passage 4 is connected between the solenoid valve 25 and the suction pump 26.

Next, in order to simultaneously and continuously analyze multiple components using the apparatus configured as described above, the sample gas S
From the sample gas inlet 14 into the sample gas inlet 2. As a result, first, the sample gas S
It is first supplied to a cell (not shown) of the IR analyzer 1. The FTIR analyzer 1 irradiates the sample gas S accommodated in the cell with infrared light and guides the transmitted infrared light to a detector (not shown) to convert the interferogram of the sample gas S. obtain. This interferogram is converted into a power spectrum of infrared light transmitted through the sample gas S by a fast Fourier transform (FFT) in the FTIR data processing unit 8 of the computer 7.

Further, the FTIR data processing section 8 obtains an absorption spectrum of infrared light by the sample gas S based on a ratio of the power spectrum to a power spectrum of a separately obtained reference gas. Based on the absorbances at a plurality of wavenumber points in the absorption spectrum, the concentration of some (single component or multicomponent) of the components contained in the sample gas S is calculated.

By repeating a series of processes from the acquisition of the interferogram to the calculation of the concentration at regular time intervals (usually several seconds), continuous measurement values of these component concentrations can be obtained. These continuous measurement values are sequentially stored in the temporary storage unit 10 of the FTIR analyzer indication value. However, there is an upper limit to the amount of data that can be stored, and measured values before a certain time are sequentially discarded.

As described above, the sample gas supplied to the cell of the FTIR analyzer is discharged from the cell outlet. Here, the analysis by the FTIR analyzer is non-destructive, that is, the analysis is not accompanied by alteration or decomposition of the sample gas. Further, when the FTIR analyzer is used for continuous analysis of gas components, the flow rate of the sample gas is generally set to a considerably large value (usually 10 to increase the response).
２０20 l / min).

[0019] By the above reasons, the portion of the sample gas discharged from the FTIR spectrometer cell may be a sample gas S of less other analyzers the more required flow rate.
In the sampling flow shown in FIG.
A part of the sample gas S discharged from is supplied through the gas flow path 4 to the analyzers 3A and 3B of the THC meter and the O ₂ meter. In these THC meter analyzer 3A and O ₂ meter analyzer 3B, each predetermined measurement with respect to the supplied sample gas S (continuous measurement of THC and O ₂ concentration) is performed. The concentration instruction of the continuous measurement in the THC analyzer 3A and the O ₂ analyzer 3B is sent to the temporary storage unit 1 of another indicated value of the analyzer via the data reading unit 9 of the other analyzer.
1 are sequentially stored. However, there is an upper limit to the amount of data that can be stored, and measured values before a certain time are sequentially discarded.

The instructions of the other analyzers read into the computer 7 as described above can be output to the operation / output unit 13 together with the instructions of the FTIR analyzer. In this case, in the FTIR analyzer, a time lag occurs between the actual change in the sample gas concentration and the change in the indicated value for the time required for the FFT processing and the concentration calculation processing (typically, several seconds). In the THC analyzer 3A and the O ₂ analyzer 3B provided downstream of the FTIR analyzer 1, the time required for the sample gas S to reach the analyzer is longer than the FTIR analyzer 1 (later). .

Due to these factors, the dead time between the FTIR analysis unit 1 and the concentration instruction of the other analysis unit 3 does not match in many cases. Therefore, the dead time (or the size of the shift) is obtained in advance by, for example, flowing a standard gas and stored in the arithmetic processing unit 12 of the computer 7.

[0022] For example, FTIR analysis unit 1, THC meter analyzer 3A, the dead time of the O ₂ meter analyzer 3B respectively,
T _FT, T _HC, and T _02, and a _{T FT> T HC> T 02} . Then, the FTIR analyzer 1 is used as a reference. Values (T _FT −T _HC ) and (T _FT −T ₀₂ ) are stored as the dead time shift values of the THC analyzer 3A and the O ₂ analyzer 3B, respectively. Then, for the FTIR analysis unit 1, the latest indicated value (shift 0), the other analysis units 3A, 3
For B, (T _FT −T _HC ) and (T _FT −
T ₀₂ ) Temporary storage unit of analyzer indication by using previous indication value
It is taken out from 0 and 11 and output to the operation / output unit 13. By doing so, for example, FIG.
As shown in (C), the instruction of each analyzer 1, 3A, 3B is given to the analyzer having the largest dead time (in this example, F
(TIR analyzer).

In the analysis of gas components by an FTIR analyzer, a cell having a capacity of several tens to several hundreds of ml is often used, and the sample gas is rounded in the cell.
On the other hand, a sufficiently small cell may be used for the THC meter and the O ₂ meter,
The roundness is small. Comparing the response speeds of the FTIR analyzer and other analyzers, the difference in roundness also contributes to
FTIR analyzers are often several times slower. However, in this embodiment, the sample gas S that has already been lost in the cell of the FTIR analyzer 1 is supplied to the THC analyzer 3A and the O ₂ analyzer 3B. Therefore, it is possible to align FTIR analysis unit 1 and the THC meter analyzing unit 3A, the response speed of the O ₂ meter analyzer 3B substantially.

[0024] Incidentally, the response speed of the analyzer, because some factor other than rounding of the sample gas, the response speed of this also in Example, FTIR analyzer 1 and the THC meter analyzer 3A, O ₂ meter analyzer 3B May have some differences. Even in such a case, if the response speed is slower,
The response value of the sample gas S can be adjusted, for example, by moving and using the indicated values stored in the temporary storage units 10 and 11 in the arithmetic processing unit 12 and using the moving average. The required average number of times may be obtained in advance using a standard gas or the like, and stored in the arithmetic processing unit 12.

As described above, the arithmetic processing section 12 can calculate other analysis values in real time as needed from the indicated values of the analyzers whose timing and response speed are substantially aligned. For example, in the case of analysis of engine exhaust gas, CO, CO ₂ instruction from the FTIR analysis unit 1, T
THC instruction from HC meter analyzer 3A, O ₂ meter analyzer 3B
O ₂ instructions from, and the like coal water ratio of fuel stored in advance (C / H), can be calculated air-fuel ratio (A / F). The following shows an example of several types of A / F calculation methods.

[0026]

Examples of other components include a THC instruction from the THC analyzer 3A and a CH from the FTIR analyzer 1.
₄ By taking the difference from the instruction, non-methane hydrocarbons (NTH
C) can also be measured. Conventional NTHC analyzers use a method of separating CH ₄ from other measurement components using the principle of gas chromatography, and a method of selectively burning components other than CH ₄ with a catalyst. However, according to this example, such a technique for separating the gas component itself is unnecessary.

The load on the computer 7 for the calculation processing from the instruction of the analyzer as in the above-described example is smaller than that of the FFT processing performed by the FTIR data processing unit 8 and the like. Therefore, each component used in the calculation (and other components)
It is sufficiently possible to simultaneously output the indicated values and the calculated values.

Further, in addition to calculating other analysis values as described above, the indicated value of a certain analyzer can be used for interference correction of the indicated value of another analyzer. For example, FT
In the case where the indication of SO ₂ obtained only by the IR analyzer 1 is subject to interference corresponding to the concentration of THC in the sample gas S, the SO ₂ is corrected using the indicated value of the THC analyzer 3A. What is necessary is just to output. By employing such a method, it is possible to reduce interference that cannot be corrected by a single analyzer.

In the above-described embodiment, a part of the sample gas S discharged from the FTIR analyzer 1 is analyzed via the gas flow path 4 by the analyzers 3A and 3B of the other analyzers, the THC meter and the O ₂ meter. , But this invention,
The present invention is not limited to this. For example, the present invention can be applied to a case where the sample gas S cannot be collected from the FTIR analyzer 1 to the analyzer 3 of another analyzer due to a difference in sampling temperature.

That is, although not shown, the above-mentioned case is also applicable to the case where the FTIR analysis section 1 and the analysis section 3 of another analyzer are provided in parallel, and the sample gas S is supplied to each of them in parallel. In the same manner as in the embodiment, reading into the computer 7 and calculation of A / F and the like are possible. In this case, the timing correction by the buffer is performed in the same manner.

In this configuration, there may be a considerable difference in response speed between the FTIR analyzer and other analyzers. Thus, the difference can be reduced. The required average number of times is obtained in advance by flowing a standard gas or the like, as in the case of the timing shift.
May be stored in the memory.

In the present invention, other analyzers used in combination with the FTIR analyzer include the above-mentioned T analyzer.
Is not limited to HC meter and O ₂ meters, it is also possible to use other analyzers such as infrared gas analyzer.

[0034]

As described above, according to the present invention, the FTIR analyzer instructions and the instructions of other analyzers read into the computer of the FTIR analyzer are temporarily stored in the temporary storage unit, so that the FTIR analyzer is temporarily stored. The difference in response speed between the analyzer and another analyzer can be corrected and simultaneously displayed and output. Thus, instructions from a plurality of analyzers having different dead times and response speeds can be obtained as outputs from a single analyzer having substantially uniform response speeds. Thus, comparison of readings, such as uptake into the host computer, the handling of the subsequent measurement data (instruction value) is facilitated.

Then, by directly reading the instructions of other analyzers into the computer of the FTIR analyzer, other analytical values calculated using the instructions of these analyzers are also calculated in this computer, and the original values are obtained. It can be output simultaneously with the indicated value. Since the response difference between the indications of these analyzers can be almost matched as described above, a highly reliable calculated value can be obtained. Furthermore, since these calculated values are obtained directly from the FTIR analyzer, complicated calculations and equipment such as a host computer for the calculation are not required, and since the calculated values are obtained in real time, transient phenomena can be monitored. is there. In addition, an instruction value corrected for interference can be output using an instruction from another analyzer, and the performance of the analyzer itself can be improved.

In addition, F, which has a large amount of gas in the cell,
When the sample gas discharged from the TIR analysis unit is supplied as a sample gas to the analysis unit of another analyzer having a small gas rounding, the difference in response speed caused by the gas rounding can be further reduced. In this configuration, since the number of common parts of the piping is increased, a difference due to sampling conditions such as the presence or absence of gas loss in the piping is less likely to occur, and the reliability of simultaneous measurement can be improved.

As described above, according to the present invention, the FTIR
Multiple components including components that cannot be measured by the analyzer can be simultaneously and accurately analyzed in real time and continuously in real time.

[Brief description of the drawings]

FIG. 1 is a diagram showing an apparatus and a signal flow for implementing a multi-component simultaneous and continuous analysis method of the present invention.

FIG. 2 is a diagram showing an example of a gas sampling flow in the apparatus.

FIG. 3 is an operation explanatory diagram of the present invention.

FIG. 4 is a diagram for explaining a conventional technique.

[Explanation of symbols]

1 ... analyzer of FTIR analyzer, 3 ... analyzer of analyzer other than FTIR analyzer, 7 ... computer of FTIR analyzer, 10, 11 ... temporary storage unit.

────────────────────────────────────────────────── ─── Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01N 21/00-21/01 G01N 21/17-21/61 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. An instruction from another analyzer other than the FTIR analyzer is directly read into a computer for control and data processing of the FTIR analyzer, and the instruction and the instruction of the FTIR analyzer are temporarily stored in a temporary storage unit. , Dead time difference
Timing and response after correcting for differences in
A multi-component simultaneous and continuous analysis method characterized by displaying and outputting both instructions at almost the same speed . 2. The method according to claim 1, wherein the analyzed sample gas discharged from the analyzer of the FTIR analyzer is supplied as a sample gas to an analyzer of another analyzer other than the FTIR analyzer. Component simultaneous and continuous analysis method.